returns

Boolean

example

import {A} from 'ts-toolbelt'

type test0 = A.Extends<'a' | 'b', 'b'> // Boolean
type test1 = A.Extends<'a', 'a' | 'b'> // True

type test2 = A.Extends<{a: string}, {a: any}>      // True
type test3 = A.Extends<{a: any}, {a: any, b: any}> // False

type test4 = A.Extends<never, never> // False
/// Nothing cannot extend nothing, use `A.Equals`